Apparatus for using heat pipes in controlling temperature of an LED light unit

ABSTRACT

A light emitting diode (LED) light unit is disclosed. For example, the LED light unit includes at least one support plate having one or more inner openings. At least one LED array may be coupled to an LED board. The LED light unit also includes at least one heat pipe coupled to the LED board, wherein said LED board is coupled to the at least one support plate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 60/817,880 filed on Jun. 30, 2006, which is hereinincorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to removing heat from an LEDlight unit and more specifically to heat pipes for controllingtemperature of an LED light unit.

BACKGROUND OF THE INVENTION

In the past light emitting diodes (LEDs) were limited to power levelsunder a watt. LEDs are now available in packages over five watts. LEDsare now also available with efficiencies of 100 lumens/watt. Theserecent advancements have enabled many new applications for LEDs. Oneexample is the use of LEDs for warning devices such as beacon lights.Beacon lights typically emit light with a limited vertical beam spreadand at all radials throughout the omnidirectional 360°. Morespecifically LEDs can be used in strobing beacon applications wherexenon strobe tubes were used in the past. Using LEDs (light emittingdiodes) to produce warning devices which produce a flash similar to theunits employing xenon flashtubes have been discussed. In manyapplications these devices are positioned on the tops of radiotransmission towers, wind turbine generators, refinery stacks, and thelike. Such locations make the performance of routine maintenance (suchas replacing the flashtube) extremely difficult. The ability to use LEDswith their longer lifetime in place of the xenon tube provides a majoradvantage.

To provide light output in these devices similar to the xenon flashtuberequires a large number of LEDs. For example the Federal AviationAdministration requires the operation of white flashing devices at thetops of radio towers during daylight hours. For medium intensityapplications, such devices must be capable of producing a minimum of20,000 effective candelas of light output. To produce this light outputusing LEDs may require approximately 400 five watt LEDs. Because thelight is flashing the LEDs would be run at a duty cycle of less than100%.

Packaging this large number of LEDs in the small space required for alight signal results in a large concentration of heat. Buildup of heatin an LED die can lead to shorter lifetimes and, in extreme cases,failure of the LED device. Internal die temperatures for LEDs should bekept low in order to maximize the performance and lifetime of the LEDs.Maximum LED die temperatures range from about 125° C. to 150° C.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a light emitting diode(LED) light unit. The LED light unit comprises at least one supportplate having one or more inner openings, at least one LED array coupledto an LED board and at least one heat pipe coupled to said LED board,wherein said LED board is coupled to said at least one support plate.

In another embodiment, the present invention provides an LED light unitcomprising a plurality of support plates, wherein each one of saidplurality of support plates has one or more inner openings and each oneof said plurality of support plates is stacked vertically and coupled toa center column. The LED light unit also comprises at least one LEDarray coupled to an LED board, a heat collector coupled to said LEDboard and at least one heat pipe coupled to said heat collector. The atleast one heat pipe may be coupled to said heat collector such that saidat least one heat pipe is directly beneath and parallel to said at leastone LED array, wherein said at least one heat pipe coupled to one ofsaid plurality of support plates.

In another embodiment, the present invention provides an LED light unitcomprising at least one LED array coupled to an LED board, at least oneheat collector, at least one LED board, wherein said LED board iscoupled to said at least one heat collector and at least one heat pipecoupled to said heat collector.

BRIEF DESCRIPTION OF THE DRAWINGS

The teaching of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a high level block diagram of an exemplary embodimentof the present invention;

FIG. 2 illustrates a high level block diagram of another exemplaryembodiment of the present invention;

FIG. 3 illustrates an exemplary support plate and heat pipe;

FIG. 4 illustrates a more detailed view of an exemplary heat pipe andassociated structures;

FIG. 5 illustrates an exploded view of an exemplary embodiment of thepresent invention;

FIG. 6 illustrates an exemplary center column of the present invention;

FIG. 7 illustrates a top view of an exemplary heat sink;

FIG. 8 illustrates an exemplary fully assembled side view of the presentinvention; and

FIG. 9 illustrates an exemplary fully assembled isometric view of thepresent invention.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures.

DETAILED DESCRIPTION

FIG. 1 illustrates a high level block diagram of an exemplary embodimentof a light emitting diode (LED) light unit 100 of the present invention.The LED light unit 100 may be, for example, a beacon placed on radiotransmission towers, wind turbine generators, refinery stacks and thelike. The LED light unit 100 may utilize LEDs that flash, for example ina strobe unit, or LEDs that continuously emit light, for example thatare always in an on position. The LED light unit 100 may include atleast one support plate 102 ₁ to 102 _(n). Hereinafter, the supportplates 102 ₁ to 102 _(n) may be referred to individually or collectivelyas support plate 102. The support plate 102 may be any geometry, forexample circular or any polygonal shape, for example a square, hexagon,octagon and the like. In an exemplary embodiment, the support plate 102may be circular for the purposes of discussing the present invention.Furthermore, the support plate 102 may be constructed from any thermallyconductive material such as, for example, copper, aluminum and the like.

The support plate 102 may have at least one array of LEDs (not shown)coupled to the support plate 102. In an exemplary embodiment, the LEDlight unit 100 includes three support plates 102. One skilled in the artwill recognize that the LED light unit 100 is not limited to any numberof support plates 102. The LED light unit 100 may be modular. That is,the LED light unit 100 may have support plates 102 added or removed asthe number of LEDs required changes due to the increased or decreasedefficiency of the LEDs that are used, or as required by the photometricrequirements of a particular application.

Each support plate 102 has one or more one or more inner openings 106.In one embodiment, the one or more one or more inner openings 106 are aconcentric circular opening when the support plate 102 has a circulargeometry, for example. In another embodiment, the one or more inneropenings 106 may be openings 310 at points around the support plate, asillustrated in FIG. 3 and discussed below. The one or more one or moreinner openings 106 allow heat pipes 104 to extend vertically up througheach support plate 102. The specific alignment of the heat pipes 104will be discussed below. Each support plate 102 may have at least oneheat pipe 104; however, those skilled in the art will recognize thateach support plate 102 may have any number of heat pipes 104 appropriatefor sufficiently removing heat away from the LED arrays.

In an alternative embodiment of the present invention, the LED lightunit 100 may have no support plates 102. For example, the heat pipes 104may themselves function as all or part of the support plates 102. Theheat pipes 104 may run vertically to a top plate that holds all the heatpipes 104 in position.

Each support plate 102 may be stacked vertically above one another asillustrated by FIG. 1. Each support plate 102 may be coupled to a centercolumn 108. Collars (not shown) may be coupled to the center column 108to level each support plate 102. One skilled in the art will recognizethat the center column 108 may be a single unified segment or aplurality of smaller segments combined to form the center column 108. Inaddition, the center column 108 may be constructed from a thermallyconductive material such as, for example, copper, aluminum and the like.

As discussed above, the amount of light output required by the LED lightunit 100 causes LED light unit 100 to generate a large amount of heat.Moreover, due to the packaging of a large number of LEDs required tooutput up to 20,000 effective candelas or more of light in a small spaceresults in a large concentration of heat. The design of the presentinvention allows such large number of LEDs to be packaged in a smallspace while dissipating the heat away from the LEDs. As a result, thelifespan of the LEDs will be greatly extended and a minimal amount ofmaintenance is required.

The heat pipes 104 provide a way to more efficiently transfer thermalenergy away from the LEDs. As heat is generated by the LEDs it isconducted to the support plates 102. The heat pipes 104 may transfer theheat towards the center of the support plate 102 and up towards the openair or a heat sink, as will be discussed below. For example, each levelof support plates 102 may have a plurality of heat pipes 104 that allextend vertically upward. Alternatively, each level of support plates102 may have the heat pipes 104 of each respective support plate 102coupled to a central heat pipe (not shown) that runs vertically up thecenter of the LED light unit 100. However, the alternative embodimentwill result in an increased number of thermal interfaces between theheat pipes 104 and the heat sink or open air. Thermal interfacesgenerally add thermal resistance.

The heat pipes 104 may be constructed from a thermally conductivematerial such as, for example, copper, aluminum and the like. The heatpipes 104 are hollow providing an interior volume. The interior volumeof the heat pipes 104 may be filled with a small amount of working fluidsuch as, for example, water, any alcohol (e.g., ethanol) or a mixture offluids and a vapor phase of the selected working fluid. An inner wall ofthe heat pipes 104 may be sintered or grooved to exert a capillary forceon the working fluid.

The heat pipes 104 dissipate the heat away from the LEDs by employingevaporative cooling to transfer thermal energy from one point to anotherby the evaporation and condensation of the working fluid. For example,the vaporization of the working fluid inside the heat pipes 104 by theheat generated by the LEDs causes vapor of the working fluid to form andrise to a highest point of the heat pipes 104, where the vapor is thencondensed by the cooler air back to liquid form and then the liquidfalls back to the bottom of the heat pipes 104 to start the process overagain. The boiling point of the working fluid may be much lower insidethe heat pipe 104 than the boiling point of the working fluid outside ofthe heat pipe 104 due to the reduced pressure inside the heat pipes 104.Consequently, the heat generated by the LEDs may be enough to vaporizethe working fluid inside the heat pipes 104 at lower temperatures thanin standard atmospheric conditions.

It should be noted that the present invention is not limited to anyparticular heat pipe structures. Heat pipes as used in the presentinvention having alternative structures are within the scope of thepresent invention. For example, heat pipes 104 may actually be a heatplate or a sheet. In addition, the heat pipes 104 of various shapes(e.g., circular or polygonal) and sizes which make use of this sameliquid/vapor thermal transfer mechanism may be used.

The working fluid used inside the heat pipes 104, a diameter and alength of the heat pipes 104 are a function of the temperatureconditions in which the heat pipes 104 must operate. In an exemplaryembodiment of the present invention, the heat pipes 104 contain water.Regarding the diameter of the heat pipes 104, the distance the heat musttravel may dictate the diameter. Larger diameters are more expensive andmore difficult to move or bend slightly in manufacturing. In anexemplary embodiment of the present invention, the diameter of the heatpipes 104 is approximately 5 to 6 millimeters (mm). Similar to diameter,the distance the heat must travel and the cost to manufacture maydictate the length of the heat pipes 104. In an exemplary embodiment ofthe present invention, the length of the heat pipes 104 is approximately0.5 ft. to 2.0 ft.

FIG. 2 illustrates a high level block diagram of another exemplaryembodiment of an LED light unit 200 of the present invention. The LEDlight unit 200 is similar structurally to the LED light unit 100 in allrespects. However, the LED light unit 200 may comprise at least one airintake 202 to provide greater transfer of heat away from the heat pipesand, therefore, away from the LEDs. As illustrated by FIG. 2, air intake202 may provide an air flow through the one or more one or more inneropenings 106 and/or the center column 108 to create an “updraft” to helpfacilitate the heat transfer provided by the heat pipes 104.Alternatively, a cooling fan or other cooling mechanism may be used tocreate the “updraft”. In one embodiment, heat sink fins may be attachedto the heat pipes 104 within the center column 108 to increase thecooling.

FIG. 3 illustrates an exemplary support plate 102 and one heat pipe 104in greater detail. As discussed above, each support plate 102 may haveat least one array of LEDs 302. The LED array 302 comprises a pluralityof individual LEDs placed adjacently to one another generally in a line,as illustrated in FIG. 3. For example, the LEDs may be slightlystaggered along the line. The LEDs used in LED array 302 may be any typeof LED. For example, the LEDs may be any color or constructed from anymaterial.

The LED array 302 may be coupled to an LED board 304. The LED board 304may be constructed from any thermally conductive material such as, forexample, copper, aluminum and the like. The LED board 304 may then becoupled to a heat collector 306. The heat collector 306 may also beconstructed from any thermally conductive material such as, for example,copper, aluminum and the like. The heat collector 306 may be any shapeor have any dimensions. For example, the heat collector 306 may be aplate and the dimensions of the heat collector 306 may be similar ingeometry to the LED board 304.

The heat pipe 104 may be coupled to the heat collector 306. However tominimize the number of interfaces that the heat must be carried throughand to maximize the heat transfer away from the LED array 302, the heatpipe 104 may be directly coupled to the heat collector 306. Moreover,the heat pipe 104 is strategically placed directly underneath the LEDarray 302 such that the heat pipe runs parallel to the LED array 302.Consequently, the distance between the heat pipe 104 and each of theLEDs in the LED array 302 is minimized. This is illustrated by FIG. 3.This particular placement of the heat pipes 104 relative to the LEDarray 302 also helps to maximize the efficiency of the heat transferaway from the LED array 302. In an alternative embodiment of the presentinvention, the heat pipe 104 may be coupled directly to the LED board304 without the use of a heat collector 306.

In one embodiment, the heat pipe 104 runs initially parallel to thesupport plate 102 and is eventually angled towards the one or more inneropenings 106 of the support plate 102. At some point, depending on arelative location of the support plate 102, the heat pipe 104 may bebent to extend vertically upwards. The precise point at where the heatpipe 104 begins to extend vertically upwards will be discussed infurther detail below with reference to FIG. 5.

A thermally conductive interface material may be placed in between theLED board 304 and the heat collector 306. The thermally conductiveinterface material helps to maximize the heat transfer between the LEDboard 304 and the heat collector 306, which in turn will maximize theheat transfer to the heat pipe 104. The thermally conductive interfacematerial may be for example, a phase change material, a thermal grease,a thermal epoxy or a thermal tape.

A more detailed view of the heat pipe 104 and the associated structuresare illustrated in FIG. 4. FIG. 4 illustrates a side view of the heatpipe 104, LED array 302, LED board 304 and heat collector 306. Althoughnot illustrated, the phase change material may be placed in between theLED board 304 and the heat collector 306, as discussed above.

In addition, FIG. 4 illustrates a coupling joint 312. The coupling joint312 may be formed by welding, soldering or gluing. In another embodimenta mechanical means, such as for example, clamps or screws can be used.Consequently, the number of thermal interfaces may be minimized bycoupling the heat pipe 104 directly to the heat collector 306. The heatcollector 306 may then be coupled directly to the LED board 304.

Referring back to FIG. 3, the support plate 102 may also comprise arecess 308 for receiving and mounting the LED array 302, LED board 304,heat collector 306 and heat pipe 104. However, as discussed above, in analternative embodiment of the present invention the LED light unit 100may have no support plates 102 and the combination of LED board 304,heat collector 306 and the heat pipes 104 may function as the supportplate 102.

In an exemplary embodiment of the present invention, the support plate102 may have six recesses 308 for receiving and mounting six LED arrays302 and heat pipes 104. Those skilled in the art will recognize that thepresent invention may have any number of recesses 308 for receiving andmounting any number of LED arrays 302 and heat pipes 104.

Although the exemplary embodiment illustrated in FIG. 3 illustrates theLED array 302, LED board 304 and heat collector 306 in a horizontalconfiguration, one skilled in the art will recognize that the LED array302 may have a different mounting configuration. For example, the LEDarray 302 may be mounted in a vertical plane instead of a horizontalplane as illustrated in FIGS. 3 and 4. The heat pipes 104 may have lessbends but still run vertically to a top plate that holds all the heatpipes 104 in position.

In addition, the support plate 102 may also include at least one opening310. As discussed above, the one or more openings 106 may also includereference to openings 310 and may be used interchangeably herein. Theopenings 310 may provide for proper alignment of the heat pipes 104, aswill be discussed below with reference to FIG. 5. The shape and size ofthe openings 310 allow the support plate 102 to be used for any levelwithin the LED light unit 100. For example, the openings 310 may beshaped as a slot. Thus, the same support plate 102 may be fabricated thesame for every level of the LED light unit 100 even though thepositioning of the heat pipes 104 within the openings 310 may bedifferent for each level.

Notably, as discussed above, the support plate 102 is constructed from athermally conductive material such as, for example, copper, aluminum andthe like. Therefore, the present inventive design of the support plate102 provides redundancy should any of the heat pipes 104 fail. Forexample, the heat collector 306 coupled to the heat pipe 104 and LEDboard 304 is in intimate contact with the support plate 102.Consequently, if one of the heat pipes 104 were to fail, the heat may betransferred via the support plate 102 to a functioning heat pipe 104.

In addition, the present inventive design of the support plate 102allows the support plate 102 to even out the heat generated by the LEDarray 302 to be dissipated by the heat pipes 104. For example, if thesupport plate 102 comprises a plurality of LED arrays 302, one of theLED arrays 302 may run much hotter than the other LED arrays 302. Thismay cause the heat pipe 104 coupled to the hotter LED array 302 to workmuch harder than the other heat pipes 104. The support plate 102 mayalleviate this non-uniformity by tending to even out the heat generatedby the LED arrays 302 to be dissipated by the heat pipes 104.

FIG. 5 illustrates an exploded view of an exemplary LED light unit 400of the present invention. The LED light unit 400 illustrated in FIG. 5depicts four layers of support plates 102 ₁, 102 ₂, 102 ₃ and 102 ₄.However as discussed above, the LED light unit 400 may comprise anynumber of support plates 102 including no support plates 102 and isconstructed to be completely modular.

In an exemplary embodiment, when a plurality of support plates 102 isused for the LED light unit 400, a bottom most support plate 102 ₄ maynot need heat pipes 104. Rather, the base 402 holding the bottom mostsupport plate 102 ₄ may be constructed from any thermally conductivematerial such as, for example, copper, aluminum and the like andfunctions to dissipate heat away from the bottom most support plate 102₄ via a support structure, e.g. a light tower that the LED light unit400 is coupled to. However, if the base 402 is constructed from anon-thermally conductive material such as, for example, plastic, thenthe bottom most support plate 102 ₄ may also have heat pipes 104.

Each subsequent support plate 102 ₁ to 102 ₃ may have heat pipes 104extending vertically through the one or more inner openings 106 oropenings 310 (as illustrated in FIG. 3) of each of the support plates102 ₁ to 102 ₄. The heat pipes 104 of each support plate 102 ₁ to 102 ₄are aligned in a line radially outward from a top most support plate 102₁ to a support plate 102 ₃ directly above the bottom most support plate102 ₄. For example, the top most support plate 102 ₁ would have heatpipes 104 extending vertically through the one or more inner openings106. The heat pipes 104 would be directly adjacent to an edge of the oneor more inner openings 106 or opening 310 of the top most support plate102 ₁.

The support plate 102 ₂ directly beneath the top most support plate 102₁ would have heat pipes 104 extending vertically through the respectiveone or more inner openings 106 or openings 310 of both support plate 102₂ and the top most support plate 102 ₁. However, the heat pipes 104 ofthe support plate 102 ₂ would begin extending vertically upward slightlymore towards the center (i.e. radially inward) then the heat pipes 104of the top most support plate 102 ₁. Thus, the heat pipes 104 of thesupport plate 102 ₂ would extend vertically adjacent to the heat pipes104 of the top most support plate 102 ₁ linearly in a radially inwardposition. The heat pipes 104 of each subsequent support plate (e.g. 102₃) below would follow in a similar fashion. If the heat pipes runthrough an opening 310, the opening 310 may guide the positioning ofeach of the heat pipes 104 as described above.

Each support plate 102 ₁ to 102 ₄ may be coupled to the center column108. At least one collar 602 may be coupled to the center column 108 viapins (not shown), as illustrated in FIG. 6. The collar 602 providesspacing and a level for each support plate 102 ₁ to 102 ₄. In addition,the collar 602 may also be constructed from any thermally conductivematerial such as, for example, copper, aluminum and the like to alsohelp maximize the efficiency of heat transfer away from the LED arrays302 and to the heat pipes 104.

Referring back to FIG. 5, a lens cover 412 may be used to seal LED lightunit 400 and a plate 404 supporting at least one heat sink 406. The lenscover 412 may be constructed from a transparent material such as, forexample, glass or plastic in order to allow the light generated by theLEDs to exit the unit. The lens cover 412 helps to prevent exteriorelements such as, for example, moisture and dust, from entering the LEDlight unit 400.

The LED light unit 400 may also comprise at least one heat sink 406mounted on an exterior column 414 of the plate 404, as discussed above.A more detailed description of how the at least one heat sink 406 mountsto the exterior column 414 will be discussed below with reference toFIG. 7. The exterior column 414 and plate 404 may be fabricated from asingle piece of material or may be fabricated separately andsubsequently coupled together to form a single piece. In an exemplaryembodiment illustrated by FIG. 5, six heat sinks 406 are used. Oneskilled in the art will recognize that the present invention is notlimited to any particular number of heat sinks. Any number of heat sinks406 may be used for the present invention.

The plate 404 may be constructed from any thermally conductive materialsuch as, for example, copper and aluminum. The plate 404 comprisesridges 408 that may be slightly raised from a plane of the plate 404.The areas other than the ridges 408 may slope outward away from thecenter of the plate 404. The ridges 408 allow the heat sink 406 to bemounted such that air may flow underneath the heat sink 406 to maximizecooling. In addition, the ridges 408 allow any moisture to fall awayfrom the center of the LED light unit 400. Thus, moisture is preventedfrom leaking into the LED light unit 400.

The plate 404 may also comprise a plurality of holes 410 in each of theridges 408 for receiving the heat pipes 104. The heat pipes 104 extendvertically though the plate 404 and the holes 410 into the heat sink406. Thus, the heat sink 406 surrounds the heat pipes 104 to maximizethe cooling. A sealing structure, e.g., an o-ring may be placed in eachof the holes 410 to create a seal around the heat pipes 104, therebypreventing any moisture from leaking into the LED light unit 400 via theholes 410.

The heat sink 406 may comprise a plurality of fins to maximize thesurface area of the heat sink 406. This helps to maximize the coolingefficiency. In one embodiment, each heat sink 406 may comprise twoseparate parts.

FIG. 7 illustrates a top view of an exemplary heat sink 406 of thepresent invention. As discussed above, the heat sink 406 may actuallycomprise two separate parts. The two separate parts of the heat sink 406may be connected to the plate 402 via a dove tail connection 502. Asillustrated in FIG. 7, each part of the heat sink 406 has an end 512that is slightly curled. The slightly curled end 512 of each part of theheat sink 406 interlocks with a corresponding end 510 of the exteriorcolumn 414, thus forming the dove tail connection 502.

The dove tail connection 502 provides easier assembly and mounting ofthe heat sink 406 to the exterior column 414. For example, the dove tailconnection 502 allows each part of the heat sink 406 to swing open andclose. Thus, during manufacturing of the LED light unit 400, if aplurality of heat sinks 406 is used, a last one of the plurality of heatsinks 406 may be placed much easier in between the other heat sinks 406.

In addition, the heat sink 406 may comprise a plurality of grooves 504on each of the two parts of the heat sink 406. When the two parts of theheat sink 406 are coupled together, the grooves 504 create a circularaperture having a diameter substantially equal to the diameter of theheat pipes 104. The grooves 504 are also positioned to be aligned withthe position of the holes 410 of plate 404 and the heat pipes 104. Asdiscussed above, the heat pipes 104 vertically extend through the plate404 and holes 410 to be surrounded by the heat sink 406 to maximizecooling. A thermally conductive interface material may be used in thegrooves 504 to take up any gaps between the heat pipes 104 and thegrooves 504. This maximizes the thermal transfer.

In an alternative embodiment, the heat sink 406 may actually comprise asingle piece. Consequently, the heat sink 406 may have a plurality ofholes for inserting the heat pipes 104. The heat pipes 104 may have atapered end to be inserted into the holes of the heat sink 406. Inaddition, the holes may be filled with a thermally conductive interfacematerial to fill any gaps between the heat pipes 104 and the holes.

In another alternative embodiment, the heat sinks 406 and plate 404illustrated in FIG. 5, may comprise a single solid continuous piece.Similar to the alternative embodiment where the heat sink 406 is asingle piece discussed above, the single piece heat sink may have aplurality of holes for inserting the heat pipes 104. Again, the heatpipes 104 may have a tapered end to be inserted into the holes of theheat sink 406. In addition, the holes may be filled with a thermallyconductive interface material to fill any gaps between the heat pipes104 and the holes.

FIG. 8 illustrates a side view of a fully assembled exemplary LED lightunit 400 of the present invention. As illustrated by FIG. 8, the LEDlight unit 400 may be completely sealed from being exposed to externalelements such as, for example, wind, rain, hail, snow, dust, debris andthe like. This helps to ensure maximum extended life of the LEDs andminimal required maintenance of the LED light unit 400.

FIG. 9 illustrates an isometric view of a fully assembled exemplary LEDlight unit 400 of the present invention. As illustrated by FIGS. 8 and9, the LED light unit 400 is advantageously designed to be compact.Thus, the LED light unit 400 may be mounted for various applicationssuch as, for example, on tops of radio transmission towers, wind turbinegenerators and refinery stacks without the use of heavy machinery orcranes. An operator may carry the LED light unit 400.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

1. A light emitting diode (LED) light unit comprising: a plurality ofsupport plates, wherein each one of said plurality of support plates hasone or more inner openings and each one of said plurality of supportplates is stacked vertically and coupled to a center column; at leastone LED array coupled to an LED board; a heat collector coupled to saidLED board; and at least one heat pipe coupled to said heat collectorsuch that said at least one heat pipe is directly beneath and parallelto said at least one LED array, wherein said at least one heat pipe iscoupled to one of said plurality of support plates, wherein said atleast one heat pipe of an uppermost one of said plurality of supportplates is located through and adjacent to said one or more inneropenings of said uppermost one of said plurality of support plates andwherein said at least one heat pipe of each one of said plurality ofsupport plates below said uppermost one of said plurality of supportplates is located adjacent to said at least one heat pipe of saiduppermost one of said plurality of support plates in a line radiallyinward.